In recovering valuable materials, such as oil and water, from subsurface deposits, it is common to provide a tubing string down the well bore to act as a fluid conduit for bringing the material to the surface. In deposits where the reservoir pressure is insufficient, pumping action must be employed to recover the fluid. A pump may be positioned either at the surface or within the well bore to perform this function.
In operation, the tubing string has been found to work up and down on the up and down strokes of the pumping unit. This reduces the efficiency of recovery and may induce damage to the operating components. Therefore, a need has arisen for preventing the working of the tubing string during pumping.